This build would require you to send out a Druddigon into the Active Spot while you set up your Charmanders on your Bench. This deck list notably makes use of Water Energy, which can allow Druddigon to attack on occasion, and to give your Charizard ex line a recovery option.

Charizard ex's Stoke only needs one Fire Energy, and a single Stoke turn can get Steam Artillery ready the following turn.